acdii

Check out the Saito thread and ask there, you will get the answer you are looking for. Some guys swear they get more out of a 115 than can ever get out of a 125.

N1EDM

My Feedback: (2)

Thanks for that, Zor. Also, I have a question for acdii and anyone else who's dropped a 4-stroke into the P-51... have you been able to hide the exhaust? With my Saito 125, I have a right-angle adapter so I might be able to drop the exhaust straight down and out without breaking up the cowl. What methods have you tried???

Bob

acdii

Heres the 100, it sticks out a bit, but the engine is low enough.

Poitivin

I went by the FG17 which is much similar. haven't yet made the drill for the exhaust though have decided not to use the stock exhaust.
The Keleo pits style looks very nice but the level of destruction on the cowl is still significant for what I'm looking for not to speak about the spark plug that stays where the Keleo Pits style should be set and the extra weight it brings directly over the nose.
Other solution I've been looking is to use a Saito flexible exhaust pipe with a 90º right angle adapter or a TurboHeader Muffler (http://www.rcspecialties.net/products.php?model=TH12X1A & http://www.rcspecialties.net/product...del=RCS12x1/90). Either way am still to decide which way to go

raptureboy

Like it or not you are going to have to cut open the cowl to let heat out so you may as well go with the pitts and cut out the bottom

acdii

What Rapture said. You need a large opening behind the engine or you will overheat that puppy. What I did with mine is about what you need for proper cooling, and dont forget to baffle it so the air flows around the head and not around the inside of the cowl. If you look you can see the balsa baffle I made, I painted it with blue dope. Engine ran nice and cool, for the one flight I had it on, did the beautiful loop into the ground on that flight, and it hasn't flown since.

For the exhaust, get a 90* adapter and turboheader, and since its FG, you wont need a pressure tap, so make sure what ever muffle you do use, has it blocked off.

Edit, one other thing, since its gas, you will want a scavenge setup for the crank case breather, or you will muck up the inside of the cowl. I have an FG-11 on my T-Clips, and when breaking in the motor on the plane, I had the cowl off, and nothing connected to the breather nipple. I had a heck of a time cleaning up later, there was black gook all over the plane from it. I added a piece of fuel line and soft brass tubing, and put the end of it after the exhaust outlet to suck the residue out. Works like a charm.



Wow the image posting worked this time, usually I have to uncheck the box.

Poitivin

Thanks for the advice on the nipple. beginning was not aware of that though back in summer time I've seen it and made a second line down the cowl. The pics earlier were taken before
As for the muffler i know what i don't want to hear but yeah, i know I'll have to start cutting one of these days as it's the last thing I have pending. The Keleo looks really nice but there are issues with the spark plug and the supplied cable is no longer enough for a longer setup, so i might try out the turbo muffler with the right angle

This one is updated and just missing the future holes and muffler

1/2 time show

My Feedback: (78)

this is a topflite P-51 I jest built I made a mold of the bottom of wing with molded flange for gear door and a mold for the gear door.then I cut out wood sheeting installed fiberglass panel fits like a glove

1/2 time show

My Feedback: (78)

I have the molds if any body wants nice molded gear doors & molded flanged wing panels I can make a set easy now.

FlyerInOKC

My Feedback: (6)

Sent you a PM 1/2 Time Show

acdii

Thats something on my building sheet or when I get back to the Stang build. I have working inner doors that close when down, open when retracting and close again, repeat on extending too. They work great, but the doors look like crap, so will probably make some scratch molds and form them out of PVC in two parts and join them, or fiberglass.

N1EDM

My Feedback: (2)

acdii - thanks for going through the trouble of making that photo. A picture is worth a thousand words.. Thanks again, and have a nice Thanksgiving!!

Bob

N1EDM

My Feedback: (2)

I'm about 1/3 of the way through reading this thread and I've picked up a lot of info so far. But one thing is bothering me a bit....

I have a set of Lado electric retracts, the 90-degree version. Will the plane track OK with these? When I first bought them they were for another project. Now I want to put them to use on the Mustang when I see that most of you are using 85-degree retracts. Am I going to get into trouble using the 90's??

Thanks,

Bob

stevegauth30

I have 90's on mine and it tracks just fine, so long as you put a boot full of rudder on your take off roll. You'll be fine.

lfd47

My Feedback: (13)

I have Wingspan 90 degree retracts in mine. They look fine and track straight. Saito 125 with Keleo pitts muffler.

Good luck, Todd

N1EDM

My Feedback: (2)

Thanks for the feedback, guys. I'll stay with the 90-degree Lado's.

I see that Magnum RC doesn't carry them any more (I don't think anyone in the US carries Lado's now) but they handle the Wingspan electrics. What do you think of them, ldf47?? Also, how do you like the Saito 125?? I plan on putting that in mine. Are you happy with it or do you wish you had done something else? I thought I'd ask this question before I committed the Saito to the P-51. How do you like the Keleo Pitts muffler???

Bob

lfd47

My Feedback: (13)

Hi Bob,
I am very happy with the Wingspan retracts. They are well built and I really like the built in delay function that you can set by a tiny switch on the retracts. On the previous page here, I posted a video and other pictures of my retracts. I did have to dremel out a small portion of a wing rib for a snug fit, you can see it in one of the pictures. They are holding up great. I also added some triangle stock wood around the area of the landing gear to beef it up. I fly off bumpy grass and so far I have had no problems. As far as the Saito 125, I love it, tons of power, very reliable, no deadsticks. I like the Keleo exhaust, I just had to cut a small amount of cowl. Also, I have my vent from the crankcase tied to the back side of the exhaust tube so you really don't see it. I am using a APC 16X6 prop, I painted it black and white. I can't say if there is anything I would change.

Good luck, Todd

N1EDM

My Feedback: (2)

Thanks for that information, Todd. I'll look into that Keleo exhaust. I'd prefer that to having a big exhaust sticking out of an otherwise nice cowl. I'm getting fiberglass fittings (cowl and radiator air scoop) from Fiberglass Specialties. I was going to use the abs units to pull a mold, but after I added up the cost of getting everything, I was better off having Fiberglass Specialties make them for me.

If you guys have any other comments about the Lado retracts, Saito 125 or Keleo, etc., let me know.

Thanks a lot,

Bob

acdii

Unless you plan to make different molds and parts, the costs wont add up for making just one part, better off getting one already made. I wont know how the 125 Saito in the 51 will do until next year.

N1EDM

My Feedback: (2)

Thanks acdii,

Right now, I'm wondering if I ought to swap out the Saito 125 for a OS 95AX. My main concern is prop clearance. I'm using Robart 653 Robostruts and 3-1/4" wheels, so I wonder if prop clearance will be an issue??? With the 95AX, I can get by with a 14x8 prop. WIth the 125, the 16x6 has been the suggested prop.

Bob

acdii

I ran a 14X8 on my 100, and had no clearance issues, and think a 15x will work fine. I plan to run a DLE20 in my kit build, which also spins a 16x8, and didn't see any issues when I mocked it up. Here is what you can run on the 125

​

• Saito-120, 125a 14x10,15x8, 16x6

Zor

Bob,

How about using a three or four blade prop of smaller diameter ?
Would it not be more realistic for that plane ?

Zor

raptureboy

Realistic yes practical no. Full scale 51's had 4 blades to handle all that horse power without having to go to a larger diameter blade. Our smaller engines would be overloaded. A 3 blade works pretty well and lowers some of the prop noise.

acdii

3 blade is almost scale. If you stuck a scoop on top of the nose, and slimmed the lower cowl on a B model, you have the Allison powered P-51A.

Zor

Do I learn something here ?

If a prop is too small either by not having enough diameter or enough pitch I can see the engine reving up and then have its own limitaton due to the mixture scavenging; the ability of intake to move in and exhaust to move out).

If the prop is too large having a large diameter or a high pitch I can see the engine revolutions to slow down.

Any engine cannot deliver more power than its design, size and breathing ability is capable of.

Under what conditions can we consider an engine being overloaded ?

I did not here start a deviation from kit building a P51 but I cannot understand an engine being 'overloaded'. I think any engine will simply revup a prop of any size up to its engine power capability.

Of course it stand to logic that proper air flow cooling is adequate for the power it delivers.

Zor